Phonograph attachment



May 5 1931. J BURKE 1,803,692

PHONOGRAPH ATTACHMENT Filed Dec. 14, 1928 Patented May 5, 1931 r PATENTOFFICE ULYSSES ILBURKE, 01" DES MQINES, IOWA .rrionoennrnnirncmvrmApplication filed December 14, 1928. Serial No. 326,116.

' This invention relates to improvements in phonographs, andparticularly to that part of the phonograph where themechanicalvibrations of the stylus are converted into x a sound vibrations, and tothe conducting of said sound vibrations to the tone arm of the soundamplifier device.

The object of my invention is to improve the mechanism of a phonographwhich con- 'verts the mechanical vibrations of the stylus tosoundvibrations, whereby the harshness of the tones .will be greatlymodified, and wherebv clear and more distinct tones may be produced. V vo More particularly it is my object to provide in that type ofphonographs having a double' sound'box, improved means for transmit tingvibrations from the stylus to the dia- Lphragm's of the sound boxes. n

20 A further object is to provide in that type of a sound boxfor phonographs. having a double diaphragm and a' stylus bar for each of saiddiaphragms, improved means for connecting the free ends of said. stylusbars, whereby a single needle maybe employed for operating bothof saidstylus bars,

and at the: same time cause the stylus bars to be positively actuated bythe needle,and to permit free movement of the stylus bars withoutundesirable noises .due to loose connections, etc. v n I I vMy inventionconsists in. the construction, arrangement and combination ofrthevarious parts of the device,'w hereby the objects contemplated areattained, as hereinafter more fullyset forth, pointed out in my claims.and illustrated in the accompanying drawings, inwhich: I]: j.

1 -Figure 1 is' a side elevation of my-improved "device as applied to aphonograph tone arm. Figure 2 is a detail plan viewofmy improvedsound'box, a portion being cut away to show the interior construction.

Figure3- is a detail, sectional view'taken on the line 33 of Figure2r iQ Figure 4 is a detail sectional view taken on the line 44 of Figure 2.v c v The nu eral indicates the tone armiof a jsound. amplifier deviceof the usual constructhereto in the, usual manner and a stylus barcuring the needles in position.

bending movement between the members and 25. The thin portions 24 aresubstantion','h'aving at its free enda pair of substan' tially U-shapedsound armsll to which sound boxes 12 are connected. a v V The said soundboxes are spaced apart a slight distance and rigidly supported to eachother by means of transversely arranged bars 13, so that the two soundboxes are supported as a single unit. The boxes are supported in areverse manner so that the diaphragms 14 face each other. The saiddiaphragms and sound boxes are of the usual construction.

The central portions of thediaphragms are connected by a bar 15 toicausethe two diaphragms to operate in unison.

Each of the boxes 12 has a pivot supported 16, said stylus bars beingmounted on adjustable plvot members 17 and terminate in socket portions18. Each of the said socket portions is provided with a set screw 19forYsev Forconnec-ting both oi? these. sockets 18 with a singlestylus 0rneedle, I have provided a yoke bar 20 having an opening 21 for receivinga stylus 22 and a set screw 23 for rigidly securing the stylus therein.The said opening 21 is mounted half way between the ends of the stylusbar. The ends oflthe bar 20 are" tapered, in the manner clearlyillustrated in Figure 2,,to'very thin portions 24 which are connectedwith lugs 25. Each of the lugs 25 has a pin 26 for entering acorresponding socket 18, said pins being secured in position bymeans ofthe set screws 19.

It will be seen by referring to Figure 2 that the yoke bar 20 is heavilyconstructed, and that the members25 are also comparatively heavy, toprovide a rigid support for the pins 26. 'The members 20 and 25 .areconnected with very thin portions 24 to permit a slight tially in a lineextendinglongitudinally of the member 20,]and' passing through thestylus 22 so that thecomparativelyheavy body portions of the members 20and 25 are connected by the thin and flexible portion 24, in such amanner that motion from the member 20 ."will be positively imparted tothe members 25, and at the same time permit a free bending movementbetween said body members.

By placing the thin portion 24 in a longitudinal line through the needle22, it will be seen that bending movement of the member as may bepermitted, and at the same time movement positively transmitted to themembers 25 and 26. The material forming the socket members 18, the pins26 and the members 25 should be considered a lever arm for actuating thestylus bar 16, said lever arm terminating the point 24 which isconstantly under a bending strain, while the stylus is being operated,as the movement of the said stylus is longitudinally of the bar 20. Themetal of the bar 20 should be considered as a connecting link which isunder tensile and compression strains.

It is, therefore, quite important that the thin portion connecting themembers 20 an d 25 be located substantially in a line extending throughthe stylus 22, as before described. The thin portion 24 acts as a pivotconnection between said pivot members. I have found, however, that pivotconnections at this point are very undesirable, due to the fact that thetone properties and qualities produced through the movement of thestylus 22 will be greatly modified by said pivot connection, where twoindependent and separate pieces of material are connected by a thirdpivot member or pin. From a practical standpoint, it is almostimpossible to pivotally connect these members without more or lessundesirable noises and rattling.

It will be seen that if the stylus 22 is placed on a record with itspoint in the groove of the record, and the record rotated, then thepoint of the stylus will be oscillated transversely or longitudinally ofthe bar 20, and the longitudinal movement imparted to said bar-'20,which in turn will cause the lever device, comprising the socket 18, thebar 26 and the member 25, to oscillate transversely, and in turnlongitudinal movement imparted to the bar 15, which will cause thediaphragms 14- to be vibrated in unison. One of the diaphragms is movedinwardly while the other is' moved outwardly, thereby producing tones ofsome what lighter volume than those produced by the ordinary singlediaphragm, the tones of which are very clear and of a high qualityrepresenting more closely the natural tones of the original instrumentor voice. In actual practice one of the tone arms 11 is considerablylonger than the other to preventthe sound waves of one arm neutralizingthe sound waves of the other arm.

I have found by actual experiment that various tone qualities may beobtained by forming the yoke bar 20 of various kinds of metal. The tonequalities may also be somewhat varied by varying the thickness of theportions 24, which will necessarily depend largely upon the kind ofmaterial used in the body members 20 and 25.

Thus it will be seen that I have provided an attachment for phonographs,which is comparatively inexpensive to manufacture, inasmuch as thestandard parts of the sound box are utilized in my construction. Thedevice when constructed may be used to get a large number of toneefiects with a very small change in the apparatus, and when used asillustrated in Figures 1 and 2, will produce a clear tone of highquality.

I claim as my invention:

1. A phonograph attachment comprising a tone arm, a pair of sound boxesspaced apart and parallel with each other with their diaphragmsinnermost, said sound boxes communicating with said tone arm, each ofsaid sound boxes being provided with a stylus bar, a bar connecting thecentral portions of the diaphragms, and the inner ends of said stylusbars being connected to the bar, each of said stylus bars being providedwith a clamping device having a clamping socket, a stylus yoke having abar, laterally extending end portions and flexible portions connectingsaid bar and said end portions, a pin for each of said end portions forentering the clamping sockets of said stylus bars, and a stylussupported in the central portion of said yoke.

2. A phonograph attachment comprisinga tone arm, a pair of sound boxesspaced apart and parallel with each other with their diaphragmsinnermost, said sound boxes communicating with said tone arm, each ofsaid sound boxes being provided .with a stylus bar, a bar connecting thecentral portions of the diaphragms, and the inner ends of said stylusbars being connected to the bar, each of said stylus bars being providedwith a clamping device having a clamping socket, a stylus yoke having abar, laterally extending end portions and flexible portions connectingsaid bar and said end portions, a pin for each of said end portions forentering the clamping sockets of said stylus bars, and a stylussupported in the central portion of said yoke, the thin portion of saidyoke being substantially in a line. extending longitudinally of saidyoke and extending through. said stylus.

3. A phonograph attachment comprising a tone arm, a pair of sound boxesspaced apart and parallel with each other with their diaphragmsinnermost, each of said sound boxes being provided with a stylus bar, abar connecting the central portions of the diaphragms, the inner ends ofsaid stylus bars being connected to the bar, each of said stylus barsbeing provided with a clamping device having a socket, a stylus yokehaving a bar, laterally extending end portions and flexible portionsconnecting said bar and said end portions, a pin for each of saidendportions for entering the clamping sockets of said stylus bar, and astylus supported in the central portion of said yoke.

4. A phonograph attachment comprising a stylus yoke having a bar andlaterally extending end portions and flexible portions connecting saidbar and said end portions, a connecting pin for each ofsaid end portionsmounted perpendicular to said bar, said yoke having a clamping device inits central portion for receiving a stylus. s s

5. A phonograph attachment comprising a stylus yoke having a bar,laterally extending end portions adapted to be secured to the stylusbars of a double phonograph unit, thin portions connecting the bar andthe end portions, and a clamping device in the central portion of theyoke for receiving a stylus.

6. A phonograph attachment comprising a yoke bar terminating at each endin laterally extending port-ions, the nnctions of said laterallyextending portions and said bar being comparatively thin, the free endsof said laterally extending portions terminating in pins, and a stylusin the central portion of said bar.

Des Moines, Iowa, December 4, 1928. vULYSSES J. BURKE.

